The present invention relates generally to a tape cartridge and more particularly to a tape cartridge structure for storing a magnetic recording tape in a manner to enable smooth movements of the tape in the cartridge without causing unintended tape protrusion out of the cartridge, tape creasing within the cartridge, and undue drag on tape movements.
Various types of tape cartridges are known for storing a tape, such as a magnetic tape or an ink ribbon formed as an endless tape. Such tape cartridge has a tape receiving cavity for holding the tape in a tape roll wound on a single reel or as a plurality of random loops without using any reel. Tape moves along predetermined tape passageways by driving forces applied to the tape.
A typical example of an endless tape cartridge using a reel is a magnetic tape cartridge having an endless magnetic tape wound on a single reel. The tape is taken from the spool at its innermost end, guided along predetermined tape passageways, and then returned to the outermost end of said tape spool.
A typical example of an endless tape cartridge for storing an endless tape in the form of random loops includes a hollow container in the shape of a flat and substantially rectangular parallelepiped. The magnetic tape moves around a portion of the outer periphery of a pinch roller mounted in the container adjacent to a corner defined by a front wall and a side wall of said container, thence into a wide tape receiving cavity in the container; there the tape is stored as a plurality of folded random loops. From the cavity, the tape moves through tape passageways extending along the other side wall and the front wall, and returned back to the pinch roller. The front wall is provided with an opening for receiving a magnetic head and another opening for receiving an external capstan. The magnetic head engages the tape at the same time the capstan cooperates with the pinch roller to drive the tape by the rotation of the capstan.
The prior art tape cartridges of the type described above often encounter problems of tape protrusion out of the capstan opening in the front wall of the cartridge and tape creasing in a narrow tape path adjacent the capstan. The problem of tape protrusion has been caused due to the fact that the narrow tape path along the outer periphery of the pinch roller is located downstream of the contact point between the capstan and the pinch roller with respect to the direction of the tape movement. Here the tape makes frictional contact with a stationary wall of the narrow tape path, resulting in increased drag on the tape thereby causing tape protrusion out of the capstan opening immediately downstream of said capstan-pinch roller contact point. One such tape protrusion occurs, the tape within the cartridge continues outwardly more and more requiring operator intervention. Such protruded tape can entangle or twist about external components, and thereby suffer damages from cutting, creasing, etc., and its feeding operation becoming impossible.
The problem of tape creasing has also been caused when the tape is wrinkled or jammed by being caught by the stationary wall defining the narrow tape path applying undue drag on the tape. Such tape creasing can cause signal dropout errors resulting in data errors when the magnetic tape is used in a digital data recorder. Although several approaches have been suggested heretofore to prevent such problems of tape protrusion and tape creasing, none of them fully satisfies the strict reliability requirements for digital data recording.
Prior art tape cartridges for storing an endless tape in the form of random loops have also encountered the problems of tape creasing and undue drag to the tape movement caused at the entry of the tape passageway extending along the side wall of the cartridge when the tape in the form of random loops is guided from the wide tape receiving cavity into the narrow tape passageway. Such problems occur when the tape stored in the wide tape receiving cavity in the form of random loops is guided into the narrow tape passageway. That is, some of the tape loops near the entry of the tape passageway are simultaneously guided into the tape passageway resulting in creasing or a portion of the tape being guided into the tape passageway receives undue drag from other adjacent tape loops. Although several approaches have also been suggested heretofore to prevent such problems, none of them fully satisfies strict reliability requirements for digital data recording.